FIG. 1 depicts a conventional method 10 for fabricating a magnetoresistive sensor in magnetic recording technology applications. FIGS. 2-4 depict a conventional transducer 50 during fabrication using the method 10. FIGS. 2-4 are not to scale. The method 10 typically commences after a conventional magnetoresistive, or MR, stack has been deposited.
The conventional method 10 commences by providing a conventional hard mask layer, conventional pattern transfer layers, and a photoresist mask, via step 12. The conventional pattern transfer layers consist of a Cr layer and an antireflective coating (ARC) layer on the Cr layer. The conventional ARC layer aids in patterning of the conventional photoresist mask. The conventional photoresist mask has the desired pattern, which is transferred to the conventional ARC and Cr layers. The conventional photoresist mask covers the region from which the conventional magnetoresistive sensor is to be formed, as well as a line portion of the transducer distal from the sensor. However, part of the device region adjoining the magnetoresistive sensor is left uncovered.
FIG. 2 depicts plan and ABS views of the conventional transducer 50 after step 12 is performed. The conventional magnetoresistive stack 54 typically includes an antiferromagnetic (AFM) layer, a pinned layer, a nonmagnetic spacer layer, and a free layer. In addition, seed and/or capping layers may be used. The conventional magnetoresistive stack 54 resides on an underlayer 52, which may be a substrate. The conventional hard mask layer 56 is typically a material such as SiC or diamond-like carbon (DLC). The pattern transfer layers may be a hard mask layer 58 and an ARC layer 60. Also shown is the photoresist mask 62. The photoresist mask 62 includes a line frame portion 62L and a sensor portion 62S. Similarly, the hard mask layer 58 and ARC layer 60 include line frame portions 58L and 60L and sensor portions 58S and 60S.
A conventional hard mask is defined from the conventional hard mask layer 56, via step 14. Step 14 includes transferring the pattern from the conventional photoresist mask and pattern transfer layers. FIG. 3 depicts an ABS view of the conventional transducer 50 after step 14 is carried out. Thus, the conventional hard mask 56′ has the pattern of the photoresist mask 62 and pattern transfer layers 58 and 60. Thus, the conventional hard mask 56′ includes sensor portion 56S and line portion 56L. Note that in FIG. 3, the photoresist mask 62 and ARC layer 60 have been removed.
The magnetoresistive structure is defined, via step 16. Step 16 typically includes ion milling the transducer 50. Thus, the portion of the magnetoresistive stack 54 exposed by the conventional photoresist mask is removed. The magnetoresistive structure being defined may be a magnetoresistive sensor for a read transducer 50. In addition the Cr layer 58′ is typically consumed during the milling process.
The hard bias material(s) are deposited, via step 18. In addition, seed and/or capping layers may be provided in step 18. The hard bias material(s) and other layers are deposited while the conventional hard mask 56′ is in place.
The conventional hard mask 56′ is then removed, via step 20. Step 20 typically includes performing an ion mill to remove portions of the exposed hard bias materials on the sensor. A chemical mechanical planarization (CMP) is performed to remove the hard bias materials from the line frame. The hard mask 56′ may then be removed, for example via a reactive ion etch (RIE). An additional planarization is performed, via step 22. Fabrication of the conventional transducer hard bias structure is thus completed.
FIG. 4 depicts the conventional transducer 50 after step 22 is performed. Although the hard bias structure formation is complete, the conventional transducer 50 itself is not finished. Thus, the hard bias material(s) 64 are shown. In addition, the magnetoresistive sensor 54′ and portions of the magnetoresistive stack 54L under the line frame are shown.
Although the conventional method 10 allows the conventional transducer 50 to be fabricated, there are several drawbacks. There may be significant variations in the track width of the conventional transducer 50. As can be seen in FIG. 4, the track width of the conventional magnetoresistive structure is w. This conventional track width may vary greatly. As a result, processing yield and performance may be adversely affected. The hard bias materials 64 may also contaminate the surface of the conventional magnetic transducer 50. Again, performance of the conventional magnetic transducer 50 may be adversely affected. Further, structures, such as test electrodes, covered by the hard bias material may not be exposed by the CMPs used to remove the hard bias materials 64 from the line frame 56L/58L/60L. Consequently, conventional transducers 50 fabricated together on a wafer may not be able to be tested on a wafer level.
Accordingly, what is needed is a system and method for improving the fabrication of a magnetic recording read transducer.